Trimmer chain tensioning arrangement for boring type mining machine



March 10, 1959 w. SILKS A TRIMMER CHAIN TENSIONING ARRANGEMENT FOR BORING TYPE MINING MACHINE A Filed April 5, 1957 2 Sheets-Sheet 1 IN VEN TOR.

Fig. 2

TORNEY 24 34 Q Walter Silks March 1 0, 1959' W. SILKS TRIMMER CHAIN TENSIONING ARRANGEMENT FOR BORING TYPE MINING MACHINE Filed April 5, 1957 2 Sheets-Sheet 2 s. m R Q m; MN Y N H 5 la W m T m A 2 V 7 f 7 M J v 7 7 7 5 4 7 r.- (I W? T k 6 $5 fi w United States Patent O TRIMIVIER CHAIN TENSIONING ARRANGEMENT F OR BORING TYPE MINING MACHINE Walter Silks, Downers Grove, 111., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Application April 5, 1957, Serial No. 651,027 6 Claims. 01. 262-7 This invention relates to mining machines having a plurality of rotary cutter heads adapted to cut circular kerfs in solid coal or mineral in advance of the machine, and more particularly to mining machines of the general type disclosed in Robbins Patent No. 2,705,624, which has, in addition to the rotary cutter heads, horizontally disposed chain-carrying cutter bars adapted to trim or remove the cusps left at the roof and floor of the mine between adjacent cutter heads.

It has heretofore been common practice to provide means for varying the cutting diameters of the cutter heads and for raising or lowering the machine as a whole so as to accommodate the machine to the cutting of bores of varying heights. It has also been common practice to adjust the height of the horizontal cutter bars so as to vary their cutting height with the varying diameters of the boring heads.

Among the principal objects of the present invention is to provide an improved and simplified means for driving the cutter chain.

A further object is to provide an especially compact hydraulically actuated mechanism for maintaining the cutter chains in properly tensioned condition in response to vertical adjustment of the chain-carrying cutter bars.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic representation of the front end of a mining machine having four horizontally spaced cutter heads, and illustrating the arrangement for driving and tensioning a continuous cutter chain trained over the upper and lower cutter bars of the machine;

Figure 2 is an enlarged fragmentary detail view of the righthand side of the machine of Figure 1 showing the two righthand cutter heads broken away, and with their drive shafts in section, and with the upper cutter bar disposed at an intermediate position of vertical adjustment relative to the machine;

Figure 3 is an enlarged fragmentary detail section taken generally on line 33 of Figure 2;

Figure 4 is a detail section taken on line 4--4 of Figure 3, showing one form of hydraulic actuating circuit which may be employed; and

Figure 4a is a fragmentary view of Figure 4 showing an alternate operating position of the control valve shown in the hydraulic circuit.

Referring now to details of the embodiment of the invention shown in the drawings, the machine has a supporting frame with four cutter heads of any suitable conventional form, indicated from right to left by numerals 11, 12, 13 and 14. Said cutter heads have drive shafts 111, 121, 131 and 141, respectively, each of which shafts extends into and is driven by suitable gearing (not shown) enclosed in a gear case forming part of the frame 10. The cutter heads 11 and 12 are preferably driven in a clockwise direction, and the cutter heads 13 and 14 are driven in a counterclockwise direction, as indicated by arrows in Figure 1, so as to tend to progress dislodged loose material along the floor toward a central "ice conveyor of conventional type, having an open receiving A throat indicated at 16.

tical adjustment relative to the frame 10 as by a pair of hydraulic jacks 21 and pistons 22 connected near opposite ends of said upper cutter bar. A lower cutter bar 24 is similarly arranged for vertical adjustment by a pair of hydraulic jacks 25 and pistons 26 connected to said lower cutter bar adjacent opposite ends thereof.

A continuous cutter chain 30 is trained, as usual, along a forwardly facing guideway'33 in the upper cutter bar, and a similar guideway 34 in the lower cutter bar. In the arrangement shown in Figure l, the cutter chain passes from the lower cutter bar 24 about an idler sprocket 37 rotatable on the right end of the latter, and thence inwardly about an idler sprocket 38 on a rocking member indicated generally at 39, which has a hub 390 pivotally mounted on a bearing ring 40, which in turn is mounted on the drive shaft 111 of the cutter head 11. From the idler 38 the cutter chain extends to a drive sprocket 42 which is fixed as by key 43 to the drive shaft 121 of the cutter head 12. The cutter chain is trained part way around the drive sprocket 42, and thence passes outwardly around an idler sprocket 45 rotatable on the right end of the upper cutter bar 20. From the last named idler sprocket the chain passes into the guideway 33 of the upper cutter bar and along the latter to an idler sprocket 46 rotatable on the left end of the upper cutter bar. The chain then passes to idler sprocket 47 rotatably journaled on the drive shaft 131 of cutter head 13. By journal or bearing means not specifically shown, between sprocket 47 and shaft 131, the sprocket is able to rotate counter to the direction of the shaft as is required in the present upper cutter bar 20 by a hydraulic cylinder 50, piston 501 I and piston rod 51. For convenience, the piston rod 51 is pivotally connected to the rear end of a pin 52 which passes forwardly through the right end of the cutter bar 20, and also forms a bearing support for the idler sprocket 45 (see Figure 4). The lower end of the cylinder has a pair of trunnions 55 which are pivotally mounted in ears 56, 56 at the outer end of die arm 392.

The cylinder 50 is of the double acting type, with fluid I lines 60 and 61 connected at opposite ends thereof.

The operation of the machine is as follows: Assum- I ing that the cutting diameters of the four cutter heads 11, 12, 13 and 14 are arranged for a predetermined cutstantially tangential relation to the several cutter heads along the roof and floor of the mine. Any such change in total cutting height of the machine will also be accompanied by a corresponding change in elevation 'of the machine frame as a whole, through operation of suitable elevating jacks (not shown), which are commonly used with mining machines of this type. 7

Assuming now that the upper and lower cutter bars 20 are correspondingly changed so that they are disposed respectively in a suband '24 are to be moved farther apart so as to provide an increased cutting heightfor the machine, the upper cutter bar 20 will, of course, be raised to a higher level than that. shown in Figure 2. For example, to raise the cuttingheight of the machine 6 inches, the shafts 111', 121',

131 and 141 will be raised 3 inches by conventional elevating jacks (not shown) which act between a main.

frame (not shown) and the gear case 15. The upper bar 20 will be raised 3 inches relative to the gear case. by jacks 21. And the lower bar 24' will be droppedB inches by jacks 25.

To properly understand the operation by which chain is automatically fed from one section to another section where needed when the cutting height of the machine is increased as described above, the sectionsr'ofcha'in will be referred to, for. example, as 37-42 for that sectionor' bight between sprockets 37 and 42,. etc.

Now, asthe' cutting height is. increased, chain sections 42-45, 46-47, and47 i8' will be elongated; The chain to provide for thisv elongation has'to come from somewhere, because the chain itself will not stretch. In the present'invention, it pays out from bight 37-42, which tends to straighten, thereby shifting the take-up sprocket 38 downward, whichin turn rocks the rocker member 39 in a counterclockwise direction and shifts the take-up arm 392 in an upward direction.

At'all operating heights, the chain will betensioned by hydraulic pressure applied to the tensioning cylinder 50. This will be effected automatically, by pressure lay ing against the piston 501 and, thus, the tension in the chain will at all times'begenerally proportional to the pressure within the cylinder.

The tensioning cylinderpiston 50, 51 comprises. in effect, an oleo strut or link which automatically applies a predetermined tension to the chain at all conditions of operating height, and which automatically varies its length to accomplish the desired result. This strutor link is involved in two different kinds of operation, or a combination of both, depending on whether the upper cutter bar is moved alone, whether the lower bar. is moved alone, or whether they are moved simultaneously.

When the upper cutterv bar is raised, the piston 51 is raised with it. The cylinder likewise rises with the arm 392. If there were perfect compensation, the cylinder. and piston would both rise at the same rate. As a practical matter, this does not occur and the cylinder and piston must extend or retractto compensate for this. Referring to Fig. 4, the elements making this compensation possible, and automatic, are shown. A pump 70 feeds. fluid under pressure througha valve '71 which in this case is in position to connect the inlet line 72. with the outlet line 73 which is connected through a variable pressure relief valve 74 into the cylinder line 60. By adjustment of the handle 75, the relief .valve 74 controls the outlet pressure into line 60, spilling excess through the line 76 into the tank T. As the piston 501 is moved upward, fluid on the top side will be displaced through the line 61, valve 71, line 77 into the tank T in accordance with the normal setting shown in Fig. 4. If, during the Fig. 4 setting, the piston 501 is moved downward relative to the cylinder 50, fiuid will be displaced through line 60, into the relief valve 74 and thence through line 76 into the tank providing the pressure in the relief valve is high enough to open it.

Occasionally, it will be desirable to produce slack in the chain by power, as for example when repairs are being made on the machine. This is accomplished by turning the. valve 71 to the position shown in Fig. 4a so that pressure is admitted to the line 61, onto the top side of the piston 501.

Referring now again to the two different kinds of operation involving the tensioning cylinder and piston, first consider the case where the upper bar 20 is raised alone. This has been described in detail above. During this part of the operationywhen the cylinder ismoving' upward faster than the piston, fluid will be discharged out of the line 60' into tank; make up fluid will flow into the top of the cylinder thr ofugh line 61 from the tank. Under the condition in which the piston 501 moves upward at a rate faster than the upward movement of the cylinder, then, as shown in Fig.4, fluid will be displaced from the upper part of the cylinder through the line 61 into tank? while makeup fiuidcomesl into the bottom of the cylinder through line 60.

There is a second condition of operation, referred to above, involving the tensioning cylinder and piston ar rangement, that is when only the lower cutter baris moved downward. In this case the piston 501 will remain stationary' since itis' fixed to the upper cutter bar which does not move. As the lower bar moves downward it tends to straightenout the bight 3742 thereby pulling the tensioning idler 38 downward, shifting the arm 392 upward. This pushes the cylinder 50 up relative to the piston' causing fluid to be displaced through line 60 into tank'. The piston rod'end of the cylinder 56' and the line 61 are, however, filled with .oil' due to leakage past" the piston 501. The'line 77 also enters thetank' below the level of oil therein, so that'upon retractible movement of the'piston 501 with respect tothe" cylinder. 50, sufficient suction will. be created to draw make up fluid through'the lines 77 and 61 to the piston rod" end ofthe cylinder 50. 1

There is a third condition: of operation involving the tensioning cylinder and piston, namely a combination of" the first two'above-mentioned' conditions in which both the upper and lower bars are shifted away from the drive" shafts 111, 121, etc.; that is, the condition where the upper and lower cutter bars are raised and dropped respectively.

In the above three examples, the condition of moving the. cutter bars to increase the cutting height of the machine has been considered. Obviously, the reverse would.

occur when the cutter bars were moved in a direction to reduce'the cutting height of the machine.

As will be seen in Fig. 2, the hub 390 of the rocker 39 may be provided with an arcuate bearing face 393 in position to be engaged by the adjacent side of the cutter chain as the tensioning idler 38 is swung toward its uppermost position of adjustment.

Although I have shown and described a certain. em bodiment of my invention, it will be understood that various changes and modifications may be made without departing from the spirit and scope of the invention asdefined by the appended claims.

I claim: 1. In a mining machine of the boring type havinga plurality of cutting heads for forming contiguous bores: in advance of the machine, a main frame, upper and lower horizontally extending chain-carrying cutter bars mounted on said main frame immediately to the rear of' said cutting heads for vertical adjustment with respect to said main frame, a continuous cutter chain trained for movement along said cutter bars, a drive sprocket and a laterally spaced idler sprocket rotatably mounted on said main frame between said cutter bars and in inwardly spaced relation with respect to opposite outer ends of said cutter bars, tensioning means for said cutter chainincludinga rocking arm pivotally mounted on said main frame between said cutter bars and having a tension idler journalled thereon and meshing with said cutter chain, and a self-adjustinglink connected betweensaid' rocking arm and one of said cutter bars comprising a hydraulic cylinder and piston and means maintaining said cylinder and piston under pressure and accommodating movement of said cylinder and piston with respect to each I other to-compensate for differences in movement between said cutter. bars and said cylinder and piston upon vertical adjustment of said cutter bars.

2. The structure-of claim'l wherein the means maintainingpressure 'onsaid cylinder and pisto'nand' accord-J aa'moba modating movement of said cylinder and piston with respect to each other to take up for differences in movement between said cylinder and piston and said cutter bars includes valve means selectively operable to supply fluid under pressure to said cylinder to bias said tension idler in a take up direction and to client retractible movement of said idler.

3. In a mining machine of the boring type having a plurality of cutting heads for forming contiguous bores in advance of the machine, a main frame, horizontally extending upper and lower chain-carrying cutter bars mounted on said frame immediately to the rear of said cutting heads for vertical adjustment with respect to said main frame and having corner sprockets at opposite ends thereof, a continuous cutter chain trained for movement along said cutter bars about said corner sprockets, a drive sprocket rotatably mounted on said frame in inwardly spaced relation with respect to the opposite outer ends of said cutter bars and between the latter, and tensioning means for an intermediate portion of said cutter chain including a rocking arm pivotally mounted intermediate its ends on said frame between said cutter bars, a tension idler journalled on said rocking arm at one end thereof and having tensioning engagement with said cutter chain,

a self-adjusting link connected between the opposite end 25 of said rocking arm and one of said cutter bars and comprising a hydraulic cylinder and piston, means for maintaining fluid under pressure on one end of said cylinder and piston and biasing said tension idler in a tensioning direction and taking up for differences in movement between said cylinder and piston and said cutter bars upon vertical movement of at least one of said cutter bars with respect to said frame, a source of supply of fluid under pressure having connection with said cylin der and piston, and relief valve means maintaining a predetermined pressure on said cylinder and piston in a take up direction.

4. The structure of claim 3, wherein each of the cutting heads have drive shafts journalled in the frame and the drive sprocket for the cutter chain is fixed on one of said drive shafts.

5. The structure of claim 3, wherein the drive sprocket is fixed on the drive shaft of a cutting head disposed inwardly from the outermost cutting head at one side of the machine, and the rocking arm is rotatably mounted on the shaft of the outermost cutting head on the same side of the machine.

6. The structure of claim 3, wherein selectively operable valve means are provided to connect the source of supply of fluid under pressure to either end of the cylinder to bias the tension idler in a take up direction and to efiect retractible movement of the tension idler under the selection of the operation of the machine.

References Cited in the file of this patent UNITED STATES PATENTS 96,718 Meriam Nov. 9, 1869 2,610,517 Hornbostel Sept. 16, 1952 2,705,625 Robbins Apr. 5, 1955 2,743,093 Robbins Apr. 24. 1956 2,745,649 Robbins May 15, 1956 2,753,169 Joy July 3, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,877,005

March 10, 1959 Walter SiLs a I V j f It is hereby certified that error appears in the printe final 7b of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Coluihh 6; line 21, for "operation" read operator Signed and sealed this 7th day of July 1959.

SEA L) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

